This model allows the user to evaluate the Effective Dose and the Ambient Dose
Equivalent (see ICRP 116 Glossary, 2010) received by human tissue behind a
shielding material, which can be natural or artificial, caused by ionizing
radiations present outside the Earth magnetosphere.

The user defines different input parameters such as the shielding properties,
including number of layers, atomic composition and thickness of each layer, the period of
time to consider and the distance from the Sun. The user may also define the spatial scaling factor exponent (Smart and Shea, 2003).

The model is based on the Bethe-Bloch equation for the energy released in the
material by charged particles assessment (Sternheimer et al., 1984; Groom, 1993).
The information concerning particles flux is based upon data
collected by some recent satellites, such as ACE and two spacecrafts of the GOES constellation (ACE website; GOES website). The user may also evaluate the Galactic Cosmic Ray and Anomalous Cosmic Ray fluxes through the Nymmik model (ISO TS 15390, 2004; Nymmik et al., 1992, 1996), where
a prediction model is used in case of future dates inside a suitable sun-spot cycle (Hathaway, 1994).

The dose values are calculated with two method: the Effective Dose is evaluated
using specific conversion fluence-to-dose coefficients (ICRP 116, 2010; Sato et
al., 2009, 2010), while the Ambient Dose Equivalent is evaluated using the ICRU
Sphere definition (see ICRU report 33 or IAEA Glossary). The first method
provides different types of exposure, where the isotropic exposure is recommended
as the most conservative condition (see ICRP 116, 2010).

Finally, with this simplified model the user may assess the radiation
effects on targets outside the Earth magnetosphere, either during journey inside
a spacecraft or during the settlement on different celestial bodies such as planned by future
world-wide space agencies missions.